The Yaf_Plugin_Abstract class

Introduction

Plugins allow for easy extensibility and customization of the framework.

Plugins are classes. The actual class definition will vary based on the
component -- you may need to implement this interface, but the fact
remains that the plugin is itself a class.

A plugin could be loaded into Yaf by using
Yaf_Dispatcher::registerPlugin(), after
registerd, All the methods which the plugin implemented according to this
interface, will be called at the proper time.